CPS2 A Board Fried?

PCB problems and fixes
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SailorLodestar
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CPS2 A Board Fried?

Post by SailorLodestar » April 17th, 2019, 6:50 pm

So I got my first ever cabinet last weekend. A sega blast city. I needed to order new harnesses for the controls but every once in a while I will boot it up just to look at the attract mode of the PCBs I own so far. Well, this morning I powered it up and saw that there was just a blank grey screen. I thought maybe the battery had died in my Vampire Savior cartridge so I put in Street Fighter Turbo, and then Cyberbots. Nothing. I put in Captain Commando and it booted up perfectly fine. Which made me think maybe the problem was with my CPS2 A board. Well while I had the A board in and was thinking this, I noticed a clicking (I think. Or some other odd sound). I thought a spider was crawling out of my A board but it was smoke! I powered everything down. And unplugged it. There's some residue on the jamma connector on the CPS2 now. Does anyone have any idea what the **** happened?
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Re: CPS2 A Board Fried?

Post by DaveyD » April 17th, 2019, 7:26 pm

Did you connect the Jamma harness the wrong way round?

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Re: CPS2 A Board Fried?

Post by SailorLodestar » April 17th, 2019, 8:12 pm

It’s not that. There’s an indicator sticker on my harness. Also it wasn’t unplugged and reconnected between last night when it was working and this morning.
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nem
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Re: CPS2 A Board Fried?

Post by nem » April 18th, 2019, 4:10 pm

Something shorted.

Open up the casing and look for visible damage.

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Re: CPS2 A Board Fried?

Post by SailorLodestar » April 19th, 2019, 7:35 am

nem wrote:
April 18th, 2019, 4:10 MP
Something shorted.

Open up the casing and look for visible damage.
I don’t have the bits to open up security screws yet. (In mail) but when I got home, I thought I’d test one of the games that was working this morning.

Then I noticed the plastic is melted on the jamma harness and if I turn the cabinet on without attaching a game, I see the smoke immediately.

Maybe the problem can be deduced by looking at which pins are at the center of melting?
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Re: CPS2 A Board Fried?

Post by nem » April 19th, 2019, 3:32 pm

That's happened to me as well. You shorted out 5V and GND by bridging the pins. I'm surprised you didn't notice it right away. The smell is really, really bad.

You need a new jamma connector on the end of your harness.

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Re: CPS2 A Board Fried?

Post by FrancoB » April 19th, 2019, 4:27 pm

You can see that one end of the edge connector is broken. This will have made it much easier to misalign the connector as the two ends help to centralise the edge connector onto the PCB edge.

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Re: CPS2 A Board Fried?

Post by nem » April 19th, 2019, 5:51 pm

It's actually both ends. It's a common fault with Hirose connectors. The plastic becomes brittle and the first casualty is the ends of the connectors. Most of mine look like that. You have to be really careful when aligning the board.

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Re: CPS2 A Board Fried?

Post by PrincessPrinPrin » April 19th, 2019, 7:11 pm

If pin 7 had been keyed it would never have happened no matter if the plastic was broken at the sides.
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Re: CPS2 A Board Fried?

Post by SailorLodestar » April 19th, 2019, 8:06 pm

So I don't need a whole new cable set? I can just get a new connector and repin my harness to it?
Like this? https://www.ebay.com/sch/i.html?_from=R ... r&_sacat=0

Any hint at where I can get one with a keyed pin 7? (By keyed you mean there's a bump to match the empty space on the jamma connector to hold it in the proper place?)

Thank's you for all the advice everyone. I'm new to this and trying to learn.
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Re: CPS2 A Board Fried?

Post by penrhos » April 19th, 2019, 10:51 pm

Do what I do - put a blob of solder across to bridge top & bottom pins together where the key goes, works perfectly and isn't going to drop out.
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Re: CPS2 A Board Fried?

Post by dj_johnnyg » April 19th, 2019, 11:01 pm

penrhos wrote:
April 19th, 2019, 10:51 MP
Do what I do - put a blob of solder across to bridge top & bottom pins together where the key goes, works perfectly and isn't going to drop out.
I pull the pins out, then use a thin cable-tie pulled really tightly and hot glued in place for good measure.
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Re: CPS2 A Board Fried?

Post by penrhos » April 19th, 2019, 11:26 pm

I've done something like that - pulled the pins out then superglued a piece of plastic like a chunk of CD case into the slot.
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Re: CPS2 A Board Fried?

Post by SailorLodestar » April 20th, 2019, 12:04 am

penrhos wrote:
April 19th, 2019, 11:26 MP
I've done something like that - pulled the pins out then superglued a piece of plastic like a chunk of CD case into the slot.
I’ll try that.

So am I ok to just buy this?

https://www.ebay.com/itm/LOT-5-Arcade-J ... SwaB5Xl5iM

Then I can pull the pins from my old harness and just reconnect them to the same locations on the new connector?
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Re: CPS2 A Board Fried?

Post by crunchywasp » April 20th, 2019, 5:16 am

As you’re going to have to go to the hassle of removing every cable and soldering each one to a new edge connector then it’s best to buy a high quality one like:

https://akishop.jp/products/jamma-finge ... ctor-k_56h (select K-56H)

I bought keys from Neo Legend ages ago but I can’t see them on their website anymore. You can get them here:

http://www.smallcab.net/keyed-jamma-p-647.html
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Re: CPS2 A Board Fried?

Post by Layer » April 20th, 2019, 5:29 am

Indeed, with a key, this would never happen. Btw, you would have to remove it when you play a bootleg game or use an adapter to Jamma.

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Re: CPS2 A Board Fried?

Post by SailorLodestar » April 20th, 2019, 7:07 am

crunchywasp wrote:
April 20th, 2019, 5:16 am
As you’re going to have to go to the hassle of removing every cable and soldering each one to a new edge connector then it’s best to buy a high quality one like:

https://akishop.jp/products/jamma-finge ... ctor-k_56h (select K-56H)

I bought keys from Neo Legend ages ago but I can’t see them on their website anymore. You can get them here:

http://www.smallcab.net/keyed-jamma-p-647.html
Thanks, those links are super helpful.

So for the resoldering process.

-take note of current pin locations
-cut off rubber pin covers?
-desolder the pins
-solder on to same locations on the new connector

But is there any way for me to replicate the rubber covers? They're necessary, aren't they?
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Re: CPS2 A Board Fried?

Post by crunchywasp » April 20th, 2019, 7:20 am

Google ‘JAMMA pinout’ to get a pinout diagram. I’d recommend labelling each wire with the pin reference before removing them.

I’d just snip each wire as close as possible to the edge connector and strip the ends before resoldering to the new connector but you can remove the heat shrink tubing and desolder everything if you prefer.

You can remove the heat shrink with a sharp craft knife but be careful not to cut anything under it.

Replacing the heat shrink is easy - just cut it to length and remember to thread each wire through a piece before you solder it to the edge connector, then push it down over the soldered connection and heat it once your done.
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